Infrastructure for Embedded Systems. Martin Glavin. Books. Software. Caveats - 1. And now - Will it be on the Exam? Even more danger?

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1 Books Infrastructure for Embedded Systems Martin Glavin Ext Required textbooks: - An Embedded Software Primer, David Simon - Addison-Wesley: ISBN # X - Embedded System Design: An Introduction to Processes, Tools, and Techniques, Arnold Berger, CMP Books, ISBN # Suggested Textbooks: - The Art of Designing Embedded Systems, Jack Ganssle - Butterworth-Heinemann: ISBN # Embedded Systems Firmware Demystified, Ed Sutter, CMP Books, ISBN Programming Embedded Systems in C and C ++, Michael Barr, O'Reilly, Lot s of articles and handouts CSS427- Introduction to Embedded Systems 1 CSS427- Introduction to Embedded Systems 2 Software Caveats Assembler, Simulator, S-Record Generator - Available on CSS 422 website Free Hewlett-Packard C Compiler, Assembler, Linker - Available on CSS 427 website Metrowerks CodeWarrior C/C++ Compiler and Integrated Design Environment for the and ColdFire processors - Installed on lab machines - Available free from Metrowerks for 3 month duration of course - May be purchased from Metrowerks through bookstore for about $100 ( That s $1900 off list price! ) This is almost a brand new course! It is still a work in progress - This subject matter was not been taught in this way before, anywhere in Ireland This is not a programming class, although we will do some C and assembly language programming along the way You will have a significant role in shaping this class for the future - I will probably make some spectacular gaffs - You will probably get very frustrated with me or the class at least once - We ll have to learn from each other Big Win: You will be learning material that may be extremely valuable to you in your future as a Software Development Engineer CSS427- Introduction to Embedded Systems 3 CSS427- Introduction to Embedded Systems 4 Even more danger? And now - Will it be on the Exam? I haven t planned out every last detail ( understatement ) Things may change slightly, please be a little flexible - You can influence the direction of the course! The answer is Definitely maybe! The lectures are your roadmap through the material - You ll teach yourself embedded systems - I m your tour guide for the journey! Lectures Entrance Texts Trade Press Articles Home work Problems Research Papers Programming Examples Exams Exit Introduction to Embedded Systems CSS427- Introduction to Embedded Systems 5 CSS427- Introduction to Embedded Systems 6 1

2 Misc Assumptions Do you need to come to class? - No, but you are responsible for everything covered in class, and your tuition is paying for me to be here for you - Note: you are also responsible for the assigned reading (even if we don t cover it in class!) - These lecture notes are general headings. Not everything covered in class discussion is guaranteed to be in the published notes - This class is reasonably small and I take notice when you re not here - Class attendance doesn t come into play unless there is a reason to consider it No phones, children or pets I assume that: - You have a basic knowledge of computer architecture ( MSE ) - You can write a simple program in 8051 assembly language or C - You know hexadecimal and binary number systems (DS 1) - You know basic logic functions and equations If I m wrong, tell me now! CSS427- Introduction to Embedded Systems 7 CSS427- Introduction to Embedded Systems 8 Course Structure - 2 Course Structure - 3 Course is divided into major topic areas which follow the embedded design lifecycle model - Part 1: Embedded lifecycle - What is an embedded system? - Embedded microprocessors - Digital Signal Processors, DSPs - Partitioning an algorithm - HW/SW Co-design, UML-based designs, Simulation methods - Choosing components - Part 2: Design environments - Real Time Operating Systems - Software requirements - Interfacing to the real world - Designing for quality, safety and performance - Development tools - Creating executable software - Part 3: HW/SW Integration - Addressing modes - Writing in assembly language - Assembling, linking, loading, debugging - Interfacing (device-drivers, busses) - Part 4: Special topics - Internet appliances CSS427- Introduction to Embedded Systems 9 CSS427- Introduction to Embedded Systems 10 Let s Get Started Why study embedded systems? Embedded systems are key elements of our society today - An adequate supply of competent designers is a rate limiting factor in our economies ability to grow As processing power increases, we ll be able to do incredible things that we haven t begun to imagine. It is a discipline of Computer Science that has traditionally been: - Ignored - Treated as a cast-off because of its intimacy with hardware - Not well understood because of its special niche Engineers who are experienced embedded system designers are in short supply and high demand - Other countries, such as India, are filling the need It s a really fun topic! CSS427- Introduction to Embedded Systems 11 CSS427- Introduction to Embedded Systems 12 2

3 What is an Embedded System Why are Embedded Systems Different Embedded System - Any device, or collection of devices, that contain one or more dedicated computers, microprocessors, or microcontrollers - Device(s) may be local - Printer, automobile, etc. - Devices may be distributed - Aircraft, ship, internet appliance - A PC or workstation may be an embedded system Key point: - Embedded computing devices have rigidly defined operational bounds. Not general purpose computers ( PC, Unix workstation ) Dedicated to a specific task or tasks Rich variety of microprocessors ( over 300 types ) Designs are cost-sensitive Have real-time performance constraints Used with Real-Time Operating Systems (RTOS) Software failure can be life-threatening May have constraints on power consumption Operate over a wide-range of environmental conditions Fewer system resources then a desktop system All code might be stored in ROM Require specialized design tools May have on-chip debugging resources CSS427- Introduction to Embedded Systems 13 CSS427- Introduction to Embedded Systems 14 Embedded System as a hierarchy Characteristics of Embedded Systems Sensor Data Logger Sensor RS-232 Current Loop Current Loop System Processor Fiber Optic LAN Data Logger LAN Ethernet RS-232 RS-232 Remote Controller PLC RTU = FLOW of DATE INFORMATION Sensor Current Loop WAN T1 LAN DEVICE N DEVICE 3 DEVICE 1 In general, there is no architectural link to standard platforms - PC ( Win9X, NT ), MAC, HP, Sun are considered the standard platforms - Almost every design ( hardware and software ) is unique - The hardware and software are highly integrated and interdependent - ASICS, microcontrollers Typically, have moderate to severe real time constraints - Real time means system must be able to respond to the outside world May or may not have Operating System ( O/S ) services available - No printf() for debugging when there is no terminal! Tolerance for bugs is 1000X ( or more ) lower in embedded systems then in desktop computers. - May be life-threatening consequences if system fails - Often engineered for the highest possible performance at the lowest cost Embedded systems within embedded system CSS427- Introduction to Embedded Systems 15 CSS427- Introduction to Embedded Systems 16 Let s Define Some Terms and Microcontroller - An integrated circuit which forms the central processing unit for a computer or embedded controller, but requires additional support circuitry to function - MC68000, Pentium, Athlon, etc. Microcontroller - A microprocessor plus additional peripheral support devices integrated into a single package - Peripheral support devices may include: - Serial ports ( COM ), Parallel ( Ports ), Ethernet ports, A/D & D/A - Interval timers, watchdog timers, event counter/timers, real time clock ( RTC ) - Other local processors ( DSP, numeric coprocessor, peripheral controller ) ( more specifically ADuC812 ) is a microcontroller A -Based Embedded System Data Storage Program Memory Real-time Clock To outside world A Microcontroller-Based Embedded System Program Data Memory Storage Core Real-time Clock To outside world CSS427- Introduction to Embedded Systems 17 CSS427- Introduction to Embedded Systems 18 3

4 A Typical Embedded System Remember the ADuC812? Minimally Requirement for an Embedded System NMI Address Bus Data Bus Status Bus Other Peripheral Devices Clock Generation and Distribution Glue Logic and Address Decode To Outside World Random Access Memory - RAM Interface ( D/A, A/D, Digital ) Read Only Memory - ROM ( FLASH ) Communications Watchdog Timer Real Time Clock To outside world To other devices To host Computer To User I/F CSS427- Introduction to Embedded Systems 19 CSS427- Introduction to Embedded Systems 20 Common Embedded s 4-bit Microcontrollers: PIC ($1.79) 8-bit s and microcontrollers - Zilog: Z80 families ($1.39) - Intel: 8042, 8048, 8051 families ($4.95) - Motorola: 6805, 68HC11 families ($8.00) 16-bit s and microcontrollers - Intel, AMD: families - Motorola: families - NEC, Hitachi, Phillips 32-bit s and microcontrollers - Intel 80386, 80486, Pentium, StrongARM, XScale - ARM: ARM7TDMI - AMD 486E, SC520 (Aspen) - Motorola 680X0, ColdFIRE, PowerPC Recent developments Moore s Law: the complexity of integrated circuits will double every 18 months Process technology able to put more and more functionality on the same chip as the cpu Buzz Word: System on a Chip (SOC), or System on Silicon CSS427- Introduction to Embedded Systems 21 CSS427- Introduction to Embedded Systems 22 Another Example (PalmPilot) How do we use the peripherals? Motorola s Dragonball Processor The MC68328 was chosen for Palm Pilot because it is highly integrated - Performance is underwhelming ( core ) Setting up peripheral devices on a complex microcontroller is one of the most daunting tasks for any embedded systems design engineer Companies have created products based upon the simple requirement of initializing the control registers of an embedded microcontroller - Driveway from Aisys Ltd. (no longer with us) automatically generated initialization code Example: Program the address of the Vector Base Register (VBR) - In the 68000, the vector table is located from 0x to 0x000003FF - The ColdFire processor allows us to relocate the VBR to any 1M boundary in the address space of the processor - Assume <D0> = 0x , MOVEC D0,VBR would locate the vector table to the memory region 0x x300003FF CSS427- Introduction to Embedded Systems 23 CSS427- Introduction to Embedded Systems 24 4

5 Let s Define Some Terms - 2 Let s Define Some Terms - 3 Target system - The embedded system under development Host computer - The standard platform being used to develop the software and link to the target system for debugging Cross-development - Using host-based tools to create a code image that will execute on a different instruction set architecture - Example: - Write a C program on your PC - Compile it to run on a PowerPC 603 using a Cross-compiler - Create a runtime image for execution in the target system Time sensitive - If a task or operation does not complete in the specified amount of time, the embedded device will perform below design requirements - Example: A laser printer prints 8 pagers per minute instead of 10 ppm ( HP whops Lexmark once again! ) - Device continues to function Time critical - If a task or operation does not complete in the specified amount of time, the embedded device will fail. - Example: Flight control system on a fly-by-wire aircraft - Device will not operate CSS427- Introduction to Embedded Systems 25 CSS427- Introduction to Embedded Systems 26 Trends in embedded systems Embedded System - Circa 1985 Embedded system on a board Processor plus ASIC DISCRETE LOGIC FOR GLUE FUNCTIONS 8-BIT MICROPROCESSOR ( Z80 ) SOCKETED SPACING DUAL IN-LINE PACKAGE ( DIP) 4 MHz CLOCK SPEED CRYSTAL OSCILLATOR EPROMS IN SOCKETS 2K bytes 0.35 u process technology > 10 6 gates 0.18 u process technology > 4x10 6 gates System-on-Chip CSS427- Introduction to Embedded Systems 27 RAM CSS427- Introduction to Embedded Systems 28 Embedded System - Circa 2000 Surface Mount Components Crystal Oscillator Fine pitch pins microcontroller MHz CLOCK SPEED STATIC SENSITIVE 68040, 32-BIT MICROPROCESSOR Why this drive to higher integration? You tell me! ASIC Components on both sides 12 layer printed circuit board RAM Crystal FLASH MEMORY 16 MBytes CSS427- Introduction to Embedded Systems 29 CSS427- Introduction to Embedded Systems 30 5

6 Elements of an embedded system The embedded lifecycle To Outside World Key Point: Although vastly different in complexity and design, common Peripheral Bus architectural traits allow us to design and debug a wide variety of systems DEBUG Port Non-volatile memory Custom Devices EPROM, FLASH, DISK ASIC s Socketed FPGA s Hybrid PAL 4, 8, 16, 32, 4 bit bus CISC, RISC, DSP Standard Devices Integrated peripherals Volatile Memory Debug/Test Port Ports DRAM, SRAM Caches Peripheral Controllers Hybrid Pipeline Socketed Multiprocessing Systems Communication Devices Ethernet RS-232 SCSI Centronics System Clocks Proprietary RTC circuitry Software System clocks Application Code Integrated in uc Driver Code / BIOS Imported/Exported Bus Real Time Operating System Custom User Interface PCI Communications Protocol Stacks VME C, C++, Assembly Language, ADA PC-102 Legacy Code CSS427- Introduction to Embedded Systems 31 The Project Specification H/W Design Proto Debug The Integration Loop Start S/W Design Pre-Prototype New Yes Test? Stop No RTOS Integration Sys. Test Mfg. Run Test Post-Prototype No Pass Test? Re-design physical h/w and/or s/w Debug CSS427- Introduction to Embedded Systems 32 Yes Benchmarks-The Myth of MIPS Benchmarking We think that if my processor (AMD) benchmarks at 1.5 MIPS, it has better performance than your processor (Motorola) which benchmarks at 0.8 MIPS - Millions of Instructions per Second ( MIPS ) also means: - Meaningless Indicator of Performance for Salesmen MIPS is actually VAX 11/780 MIPS - The first machine to run 1 MIPS A VAX 11/780 could execute 1757 loops through the Dhrystone benchmark in 1 second - A simple C program which compiles to about 2000 lines of assembly code - Independent of O/S services If your processor executes 1757 Dhrystone loops per second, it is a 1 MIPS machine Enter compiler optimizations. Bright idea! - Let s optimize for benchmark performance and screw the real world! Real benchmarking involves careful balancing of system requirements and variables How a processor will run in your application may be very different from performance in a different application Considerations: - Overall HW design: Memory bandwidth, caches, ASICs - Software design: Assembly, C, C++, Java, libraries - Compiler: Brand, optimizations - RTOS: Optimized for certain architectures There is no easy answer to predicting performance Companies have nearly gone under due to benchmarking errors CSS427- Introduction to Embedded Systems 33 CSS427- Introduction to Embedded Systems 34 EDN Embedded Benchmark Consortium (EEMBC) Marcus Levy, Director EEMBC Technical Editor, EDN Magazine CSS427- Introduction to Embedded Systems 35 6